//I've list out the codes below, pls take a look and i'd appreciate if i can get some help. My program which is throwing index out of bound exception at line String studadmin = admin[g];
protected void Button1_Click(object sender, EventArgs e)
{
//retrieve studentdetails using List<String[];
List<String[]> stud = new List<String[]>();
int i = 0;
foreach (GridViewRow row in GridView1.Rows)
{
CheckBox check = (CheckBox)row.FindControl("CheckBox1");
if (check.Checked)
{
String [] studDetail = new String [1];
studDetail[0] = row.Cells[1].Text;
stud.Add(studDetail);
}
i++;
}
int g = 0;
foreach (String[] admin in stud)
{
String studadmin = admin[g];
// here's whr the error are prompted (IndexOutOfBoundsException),
// when it reads the following "admin", the loop just ends here with an error;
try
{
myConnection = db.getConnection();
SqlCommand cmd = new SqlCommand("sp_IPPLOAssign");
cmd.Connection = myConnection;
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#AcadYear", lb_AcadYear.Text);
cmd.Parameters.AddWithValue("#AcadPeriod", lb_AcadPeriod.Text);
cmd.Parameters.AddWithValue("#IPPProjID", lb_ProjID.Text);
cmd.Parameters.AddWithValue("#ProjSubID", "0");
cmd.Parameters.AddWithValue("#LOLoginID", ddl_LO.SelectedValue);
cmd.Parameters.AddWithValue("#LoginID", Session["UserID"].ToString());
cmd.Parameters.AddWithValue("#Adminno", studadmin);
myConnection.Open();
cmd.ExecuteNonQuery();
lb_Msg.Text = "Update Success.";
lb_error.Text = "";
}
catch (Exception ex)
{
share.WriteLog(ex.Message, "LOAssign.aspx", "Button1_Click()", "Error in updating LO.");
lb_error.Text = "Update failed.";
lb_Msg.Text = "";
}
finally
{
if (myConnection.State == ConnectionState.Open)
myConnection.Close();
}
g++; //loop the subsequent studadmin and store into database
}
refresh_gvCompany();
refresh_gvCurrent(); //refresh gridview
}
Have you confirmed your parameter names are exactly correct? Should #Adminno be #AdminNo, perhaps?
Every item in your stud is an array of String of size 1.
However, at every iteration you are increasing the index of array:
String studadmin = admin[g];
// ...
g++; // loop the subsequent studadmin and store into database
As the result, you actually try to access stud[0][0], stud[1][1]... the errors occurs here, because stud[1] contains only one item.
You need to remove i and g - they are both useless.
As your array only contains one item, it actually looks like you misunderstand usage of List and array. Probably, you want a List<string> instead of List<string[]>:
protected void Button1_Click(object sender, EventArgs e)
{
List<string> stud = new List<string>();
foreach (GridViewRow row in GridView1.Rows)
{
CheckBox check = (CheckBox)row.FindControl("CheckBox1");
if (check.Checked)
{
stud.Add(row.Cells[1].Text);
}
}
foreach (string studadmin in stud)
{
try
{
myConnection = db.getConnection();
SqlCommand cmd = new SqlCommand("sp_IPPLOAssign");
cmd.Connection = myConnection;
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#AcadYear", lb_AcadYear.Text);
cmd.Parameters.AddWithValue("#AcadPeriod", lb_AcadPeriod.Text);
cmd.Parameters.AddWithValue("#IPPProjID", lb_ProjID.Text);
cmd.Parameters.AddWithValue("#ProjSubID", "0");
cmd.Parameters.AddWithValue("#LOLoginID", ddl_LO.SelectedValue);
cmd.Parameters.AddWithValue("#LoginID", Session["UserID"].ToString());
cmd.Parameters.AddWithValue("#Adminno", studadmin);
myConnection.Open();
cmd.ExecuteNonQuery();
lb_Msg.Text = "Update Success.";
lb_error.Text = "";
}
catch (Exception ex)
{
share.WriteLog(ex.Message, "LOAssign.aspx", "Button1_Click()", "Error in updating LO.");
lb_error.Text = "Update failed.";
lb_Msg.Text = "";
}
finally
{
if (myConnection.State == ConnectionState.Open)
myConnection.Close();
}
}
refresh_gvCompany();
refresh_gvCurrent();
}
Related
I'm loading a table from a database into a CheckedListBox, and now I need to check which items are checked any time the user changes the check status of an item in the first CheckedListBox, and then add the corresponding parts of another table from my database to the second CheckedListBox.
So for example, I have chlbMeal and chlbFood. Inside the chlbMeal there are "Breakfast", "Dinner" and "Lunch". Now when the user selects any of these, I want the corresponding food options to show up in the chlbFood - for example, if "Breakfast" is checked, inside chlbFood we have "Fried eggs", "Eggs and Bacon", etc.
My project is somewhat different but that's the main the idea I want to achieve in this part of it. Here is my code:
private void chlbRadovi_SelectedIndexChanged(object sender, EventArgs e)
{
try
{
if (chlbRadovi.CheckedItems.Count > 0)
{
int[] niz = new int[chlbRadovi.CheckedIndices.Count];
chlbRadovi.CheckedIndices.CopyTo(niz, 0);
foreach (int x in niz)
{
this.tipradovaTableAdapter1.Fill(this.ignaDataSet1.tipradova);
SqlConnection con = new SqlConnection(Konekcija.con);
SqlCommand cmd = new SqlCommand("select IDTR, Naziv from tipradova where IDRad in #IDRad", con);
cmd.Parameters.AddWithValue("#IDRad", chlbRadovi.ValueMember[x]);
SqlDataReader reader;
chlbTipoviRadova.DataSource = ignaDataSet1.tipradova;
chlbTipoviRadova.DisplayMember = "Naziv";
chlbTipoviRadova.ValueMember = "IDTR";
con.Open();
reader = cmd.ExecuteReader();
con.Close();
}
}
else
{
chlbTipoviRadova.DataSource = null;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
How can I do this?
Ok, here we go. First, bind data to your first CheckedListbox:
private string connectionString = "Your connection string";
private void cbListFirst_SetDataSource()
{
// Using block will automatically close connection when it's not used anymore
using (var con = new SqlConnection(connectionString))
{
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = #"SELECT Id, Name
FROM dbo.FoodTypes";
try
{
con.Open();
var foodTypes = new List<FoodType>();
using (SqlDataReader reader = cmd.ExecuteReader())
{
// Fill items for first CheckedListBox DataSource
while (reader.Read())
{
foodTypes.Add(new FoodType()
{
Id = (int)reader["Id"],
Name = reader["Name"] as string
});
}
}
// Set first CheckedListBox DataSource
cbListFirst.DataSource = foodTypes;
cbListFirst.DisplayMember = "Name";
cbListFirst.ValueMember = "Id";
}
catch (Exception ex)
{
// Clear DataSource and handle error (should be improved)
cbListFirst.DataSource = null;
MessageBox.Show("Error", ex.Message, MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
}
After you've done that, you should have ParentIds encapsulated inside your FoodType objects inside DataSource of your first CheckedListbox. Now, you shouldn't use SelectedIndexChanged event, but ItemCheck event instead. So every time user checks or unchecks one of the items event will be triggered. Only problem you have now is that inside this event, new CheckValue of clicked item is not yet applied, but it can be handled easy since we have information about new and old value inside EventArgs. Check this out:
private void cbListFirst_ItemCheck(object sender, ItemCheckEventArgs e)
{
// Clear second CheckedListbox DataSource
cbListSecond.DataSource = null;
var ingridients = new List<Ingridient>();
foreach (var item in cbListFirst.CheckedItems)
{
// If item was previously checked, we want to skip it because it's new value is
// unchecked and we shouldn't be adding it's child items to second CheckedListbox
if (cbListFirst.Items.IndexOf(item) != e.Index)
{
var foodType = (FoodType)item;
ingridients.AddRange(GetIngridientsForFoodType(foodType.Id));
}
}
// If item was previously unchecked, it's child items won't be caught in previous loop
// so we want to explicitly include them inside this if-block if new value is checked
if (e.NewValue == CheckState.Checked)
{
var foodType = (FoodType)cbListFirst.Items[e.Index];
ingridients.AddRange(GetIngridientsForFoodType(foodType.Id));
}
// Finally, bind new DataSource
cbListSecond.DataSource = ingridients;
cbListSecond.DisplayMember = "Name";
cbListSecond.ValueMember = "Id";
}
// This method returns list of Ingridients for single FoodType
private List<Ingridient> GetIngridientsForFoodType(int foodTypeId)
{
using (var con = new SqlConnection(connectionString))
{
SqlCommand cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = #"SELECT Id, Name
FROM dbo.Ingridients
WHERE FoodTypeId = #FoodTypeId";
cmd.Parameters.AddWithValue("#FoodTypeId", foodTypeId);
try
{
con.Open();
var ingridients = new List<Ingridient>();
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
ingridients.Add(new Ingridient()
{
Id = (int)reader["Id"],
Name = reader["Name"] as string
});
}
}
return ingridients;
}
catch (Exception ex)
{
// Handle error (should be improved) and return null
MessageBox.Show("Error", ex.Message, MessageBoxButtons.OK, MessageBoxIcon.Error);
return null;
}
}
}
Now your second CheckedListbox should be filled with child values of items from first CheckedListbox.
A few months ago I made a test program for a project and everything worked fine there.
Now I am working on the program itself, so I copied the code from the test program and
changed the the names of the columns,buttons etc. so it would fit the current program.
When I try to add something into the database it does nothing on the first click, on the
second pops up an error which says that the connection is open.. I really got no idea what's
the problem. I tried to check again if I made a mistake in a column name or the database name
but everything seems to be correct.
Note: I also have a function that show data from the database and it works without any problem.
private void InsertData()
{
string NewCode = GenerateCode();
string NewSentence = txtSentence.Text;
string NewRow = NewRowNum();
try
{
string AddData = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
SqlCommand DataAdd = new SqlCommand(AddData, Connection);
DataAdd.Parameters.AddWithValue("#NewBinaryString", NewCode);
DataAdd.Parameters.AddWithValue("#NewNewSentence", NewSentence);
DataAdd.Parameters.AddWithValue("#NewRowNumber", NewRow);
Connection.Open();
DataAdd.ExecuteNonQuery();
Connection.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
//Checking the banary code in the last row
string GenerateCode()
{
string RowNo = RowFind();
int Row = int.Parse(RowNo);
int Code = Row + 1;
string Cd = Convert.ToString(Code, 2);
int Ln = Cd.Trim().Length;
if (Ln == 3)
{
Cd = "100" + Cd;
}
else if (Ln == 4)
{
Cd = "10" + Cd;
}
else if (Ln == 5)
{
Cd = "1" + Cd;
}
return Cd;
}
//Finding the last row
string RowFind()
{
Connection.Open();
string queryString = string.Format("SELECT * FROM ShopSentences");
SqlDataAdapter sda = new SqlDataAdapter(queryString, Connection);
DataTable dt = new DataTable("ShopSentences");
sda.Fill(dt);
Connection.Close();
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
string NewRowNum()
{
string Row = RowFind();
int CalcRow = int.Parse(Row) + 1;
Row = CalcRow.ToString();
return Row;
}
The connection that appears to be open is the one in the string RowFind().
Here are the other related things to the database:
public partial class frmShop : Form
{
System.Data.SqlClient.SqlConnection Connection;
public frmShop()
{
string DatabaseConnection = WindowsFormsApplication1.Properties.Settings.Default.BinaryStringsDictionaryConnectionString1;
Connection = new System.Data.SqlClient.SqlConnection();
Connection.ConnectionString = DatabaseConnection;
InitializeComponent();
}
private void frmShop_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'binaryStringsDictionaryDataSet.ShopSentences' table. You can move, or remove it, as needed.
this.shopSentencesTableAdapter.Fill(this.binaryStringsDictionaryDataSet.ShopSentences);
}
private void GetSentence()
{
try
{
Connection.Open();
SqlDataReader ReadSentence = null;
Int32 BinaryInt = Int32.Parse(txtBinaryString.Text);
string CommandString = "SELECT Sentence FROM ShopSentences WHERE BinaryStrings = #BinaryString";
SqlCommand Command = new SqlCommand(CommandString, Connection);
Command.Parameters.Add("#BinaryString", System.Data.SqlDbType.Int).Value = BinaryInt;
ReadSentence = Command.ExecuteReader();
while (ReadSentence.Read())
{
txtSentence.Text = (ReadSentence["Sentence"].ToString());
Fit = 1;
}
Connection.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
You are getting errors because you are reusing the same connection Connection.Open(); several times.
Your method InsertData() is doing this 3 times in the same method.
You should create a new instance of the connection object and dispose it on your methods.
Using Statement are the way to go.
private void InsertData()
{
using (var Connection = new SqlConnection(DatabaseConnection))
{
string NewCode = GenerateCode();
string NewSentence = txtSentence.Text;
string NewRow = NewRowNum();
try
{
Connection.Open();
string AddData = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
SqlCommand DataAdd = new SqlCommand(AddData, Connection);
DataAdd.Parameters.AddWithValue("#NewBinaryString", NewCode);
DataAdd.Parameters.AddWithValue("#NewNewSentence", NewSentence);
DataAdd.Parameters.AddWithValue("#NewRowNumber", NewRow);
DataAdd.ExecuteNonQuery();
//Connection.Close(); no need to close
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
You can save one more connection if you store the row returned by RowFind()
string RowFind()
{
using (var Connection = new SqlConnection(DatabaseConnection))
{
Connection.Open();
string queryString = string.Format("SELECT * FROM ShopSentences");
SqlDataAdapter sda = new SqlDataAdapter(queryString, Connection);
DataTable dt = new DataTable("ShopSentences");
sda.Fill(dt);
//Connection.Close();
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
}
So you would connect once instead of twice:
var Row = RowFind();
string NewCode = GenerateCode(Row);
string NewRow = NewRowNum(Row);
string NewSentence = txtSentence.Text;
Declare your connection string variable to a property so you can reuse it:
private string DatabaseConnection {get; set;}
Instead using an instance level SqlConnection you should only provide a common factory for creating a connection:
public partial class frmShop : Form
{
private string ConnectionString
{
get { return WindowsFormsApplication1.Properties.Settings.Default.BinaryStringsDictionaryConnectionString1; }
}
public frmShop()
{
InitializeComponent();
}
private SqlConnection CreateConnection()
{
var conn = new SqlConnection(ConnectionString);
conn.Open();
return conn;
}
private void frmShop_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'binaryStringsDictionaryDataSet.ShopSentences' table. You can move, or remove it, as needed.
this.shopSentencesTableAdapter.Fill(this.binaryStringsDictionaryDataSet.ShopSentences);
}
private void GetSentence()
{
try
{
using (var conn = CreateConnection())
{
var BinaryInt = int.Parse(txtBinaryString.Text);
var commandString = "SELECT Sentence FROM ShopSentences WHERE BinaryStrings = #BinaryString";
using (var Command = new SqlCommand(commandString, conn))
{
Command.Parameters.Add("#BinaryString", System.Data.SqlDbType.Int).Value = BinaryInt;
using (var readSentence = Command.ExecuteReader())
{
while (readSentence.Read())
{
txtSentence.Text = (readSentence["Sentence"].ToString());
Fit = 1;
}
}
}
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private void InsertData()
{
try
{
using (var conn = CreateConnection())
{
var commandString = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
using (var comm = new SqlCommand(commandString, conn))
{
comm.Parameters.AddWithValue("#NewBinaryString", GenerateCode());
comm.Parameters.AddWithValue("#NewNewSentence", txtSentence.Text);
comm.Parameters.AddWithValue("#NewRowNumber", NewRowNum());
comm.ExecuteNonQuery();
}
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
//Checking the banary code in the last row
string GenerateCode()
{
string RowNo = RowFind();
int Row = int.Parse(RowNo);
int Code = Row + 1;
string Cd = Convert.ToString(Code, 2);
int Ln = Cd.Trim().Length;
if (Ln == 3)
{
Cd = "100" + Cd;
}
else if (Ln == 4)
{
Cd = "10" + Cd;
}
else if (Ln == 5)
{
Cd = "1" + Cd;
}
return Cd;
}
//Finding the last row
string RowFind()
{
using (var conn = CreateConnection())
{
var commandString = "SELECT * FROM ShopSentences";
using (var comm = new SqlCommand(commandString, conn))
{
using (var sda = new SqlDataAdapter(queryString, Connection))
{
using (DataTable dt = new DataTable("ShopSentences"))
{
sda.Fill(dt);
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
}
}
}
}
string NewRowNum()
{
var Row = RowFind();
var CalcRow = int.Parse(Row) + 1;
return CalcRow.ToString();
}
}
But this is just the beginning you should not have any hard SQL dependency in your Form classes.
When sharing same SqlConnection instance several times in your code, instead of directly opening the you can rather check the connection state first and then open it if not already opened. For example:
if(Connection.State!= ConnectionState.Open)
Connection.Open();
I have a DataGridView created in C# windows forms and checkboxColumn added to it. The DataGridView is populated with other columns like Sno, AccountNo, Name, Salary (Sno is identitycolumn and primarykey).
I want to delete a row (using stored procedure) by selecting the checkbox and on button click which is out side DataGridView. Error at "FindControl".
Stored Procedure:
Create Procedure uspDeleteSelectedRow
As
Delete from EmpDetails where Sno=Sno
Go
private void btnDelete_Click(object sender, EventArgs e)
{
//Create String Collection to store IDs of
//records to be deleted
StringCollection idCollection = new StringCollection();
string strID = string.Empty;
//Loop through GridView rows to find checked rows
for (int i = 0; i < dataGridView1.Rows.Count; i++)
{
CheckBox chkDelete = (CheckBox)dataGridView1.Rows[i].
Cells[0].FindControl("chkSelect");
if (chkDelete != null)
{
if (chkDelete.Checked)
{
strID = dataGridView1.Rows[i].Cells[1].ToString();
idCollection.Add(strID);
}
}
}
if (idCollection.Count > 0)
{
//Call the method to Delete records
DeleteMultipleRecords(idCollection);
// rebind the GridView
dataGridView1.DataBind();
}
else
{
lblMessage.Text = "Please select any row to delete";
}
}
private void DeleteMultipleRecords(StringCollection idCollection)
{
//Create sql Connection and Sql Command
SqlConnection con = new SqlConnection(Helper.ConnectionString);
SqlCommand cmd = new SqlCommand();
string IDs = "";
foreach (string id in idCollection)
{
IDs += id.ToString() + ",";
}
try
{
string test = IDs.Substring
(0, IDs.LastIndexOf(","));
string sql = "Delete from EmpDetails" + " WHERE ID in (" + test + ")";
cmd.CommandType = CommandType.Text;
cmd.CommandText = sql;
cmd.Connection = con;
con.Open();
cmd.ExecuteNonQuery();
}
catch (SqlException ex)
{
string errorMsg = "Error in Deletion";
errorMsg += ex.Message;
throw new Exception(errorMsg);
}
finally
{
con.Close();
}
}
Let say this is your stored procedure:
ALTER PROCEDURE [dbo].[sp_ToDeleteEmpDetails] #Sno int
/*
(
#parameter1 int = 5,
#parameter2 datatype OUTPUT
)
*/
AS
DELETE FROM EmpDetails
WHERE Sno = Sno
RETURN
You don't need a StringCollection to delete or call the stored procedure.
private void btnDelete_Click(object sender, EventArgs e)
{
foreach (DataGridViewRow item in dataGridView1.Rows)
{
bool IsBool = false;
if (bool.TryParse(item.Cells[1].EditedFormattedValue.ToString(), out IsBool)) //<--Where: The ColumnIndex of the DataGridViewCheckBoxCell
{
using (SqlConnection con = new SqlConnection(Helper.ConnectionString))
{
using (SqlCommand cmd = new SqlCommand("sp_ToDeleteEmpDetails", con))
{
try {
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("#sno", SqlDbType.Int).Value = item.Cells[0].EditedFormattedValue.ToString(); //<--Where: The ColumnIndex of the Primary key from your DataGridView
dataGridView1.Rows.RemoveAt(item.Cells[0].RowIndex);
con.Open();
cmd.ExecuteNonQuery();
} catch (Exception) {
throw;
}
finally
{
con.Close();
}
}
}
}
}
}
Please let me know if you have some encountered problem from my given answer.
Try this solution. In my code I have class and pass a list of it to gridview as my datasource.
//Class
public class User
{
public bool Selected { get; set; }
public string UserName { get; set; }
}
//Create a list and bind to the data grid view
private void Form1_Load(object sender, EventArgs e)
{
var users = new List<User> { new User { UserName = "Jobert", Selected = false }, new User { UserName = "John", Selected = true }, new User { UserName = "Leah", Selected = true }, new User { UserName = "Anna", Selected = false } };
dataGridView1.DataSource = users;
}
//On delete
private void btnDelete_Click(object sender, EventArgs e)
{
//get data back from the source
var source = dataGridView1.DataSource as List<User>;
var selectedItems = source.Where(x => x.Selected).ToList();
foreach (var item in selectedItems)
{
//perform the delete
}
}
I want to implement a simple delete button for my database. The event method looks something like this:
private void btnDeleteUser_Click(object sender, EventArgs e)
{
if (MessageBox.Show("Are you sure?", "delete users",MessageBoxButtons.OKCancel, MessageBoxIcon.Warning) == DialogResult.OK)
{
command = new SqlCommand();
try
{
User.connection.Open();
command.Connection = User.connection;
command.CommandText = "DELETE FROM tbl_Users WHERE userID = #id";
int flag;
foreach (DataGridViewRow row in dgvUsers.SelectedRows)
{
int selectedIndex = row.Index;
int rowUserID = int.Parse(dgvUsers[0,selectedIndex].Value.ToString());
command.Parameters.AddWithValue("#id", rowUserID);
flag = command.ExecuteNonQuery();
if (flag == 1) { MessageBox.Show("Success!"); }
dgvUsers.Rows.Remove(row);
}
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message, Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Information);
}
finally
{
if (ConnectionState.Open.Equals(User.connection.State))
User.connection.Close();
}
}
else
{
return;
}
}
but I get this message:
A variable #id has been declared. Variable names must be unique within
a query batch or stored procedure.
Is there any way to reuse this variable?
Parameters.AddWithValue adds a new Parameter to the command. Since you're doing that in a loop with the same name, you're getting the exception "Variable names must be unique".
So you only need one parameter, add it before the loop and change only it's value in the loop.
command.CommandText = "DELETE FROM tbl_Users WHERE userID = #id";
command.Parameters.Add("#id", SqlDbType.Int);
int flag;
foreach (DataGridViewRow row in dgvUsers.SelectedRows)
{
int selectedIndex = row.Index;
int rowUserID = int.Parse(dgvUsers[0,selectedIndex].Value.ToString());
command.Parameters["#id"].Value = rowUserID;
// ...
}
Another way is to use command.Parameters.Clear(); first. Then you can also add the parameter(s) in the loop without creating the same parameter twice.
Rather than:
command.Parameters.AddWithValue("#id", rowUserID);
Use something like:
System.Data.SqlClient.SqlParameter p = new System.Data.SqlClient.SqlParameter();
Outside the foreach, and just set manually inside the loop:
p.ParameterName = "#ID";
p.Value = rowUserID;
I would use this:
public static class DbExtensions
{
public static void AddParameter(SQLiteCommand command, string name, DbType type, object value)
{
var param = new SQLiteParameter(name, type);
param.Value = value;
command.Parameters.Add(param);
}
}
Then, call this:
DbExtensions.AddParameter(command, "#" + fieldOfSearch[i], DbType.String, value[i]);
Error is because you are adding the same parameter again and again in each iteration of the loop.
I would move that code to a seperate method so that i can call it from multiple places as needed.
public bool DeleteUser(int userId)
{
string connString = "your connectionstring";
try
{
using (var conn = new SqlConnection(connString))
{
using (var cmd = new SqlCommand())
{
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "DELETE FROM tbl_Users WHERE userID = #id";
cmd.Parameters.AddWithValue("#id", userId);
conn.Open();
cmd.ExecuteNonQuery();
return true;
}
}
}
catch(Exception ex)
{
//Log the Error here for Debugging
return false;
}
}
Then call it like this
foreach (DataGridViewRow row in dgvUsers.SelectedRows)
{
int selectedIndex = row.Index;
if(dgvUsers[0,selectedIndex]!=null)
{
int rowUserID = int.Parse(dgvUsers[0,selectedIndex].Value.ToString());
var result=DeleteUser(rowUserID)
}
else
{
//Not able to get the ID. Show error message to user
}
}
I am trying to load data into a textbox by using a DataReader depend on the Drop down list selection. Didn't get error from this code, but the data is not loaded into textbox. please correct me.
public void text()
{
cn1.Open();
string s;
s = "select Request_Type from component where Material_Code='" + Mcodeddl.SelectedItem.Text + "' ";
SqlCommand cd1 = new SqlCommand(s, cn1);
SqlDataReader rd;
try
{
rd = cd1.ExecuteReader();
while (rd.Read())
{
TextBox4.Text = rd["Request_Type"].ToString().Trim();
}
rd.Close();
}
catch (Exception e)
{
Response.Write(e.Message);
}
finally
{
cd1.Dispose();
cn1.Close();
}
}
public void MC()
{
Mcodeddl.Items.Clear();
ListItem li1 = new ListItem();
li1.Text = "-Select-";
Mcodeddl.Items.Add(li1);
Mcodeddl.SelectedIndex = 0;
cn1.Open();
string s1;
s1 = "select Material_Code from component";
SqlCommand cd1 = new SqlCommand(s1, cn1);
SqlDataReader dr1;
try
{
dr1 = cd1.ExecuteReader();
while (dr1.Read())
{
ListItem ni1 = new ListItem();
ni1.Text = dr1["Material_Code"].ToString().Trim();
Mcodeddl.Items.Add(ni1);
}
dr1.Close();
}
catch (Exception e)
{
Response.Write(e.Message);
}
finally
{
cd1.Dispose();
cn1.Close();
}
}
If everything works fine without exceptions that is mean the connection established correctly and the SQL command is correct. I think you have to make sure about your SQL statement. Maybe it returns nothing because there are no matches.
We need more explain about your issue.