Errors when retrieving values from database determined by combobox to gridview - c#

I have a code to get all the values from database determined by a combobox to a datagridview.
But whenever i run it , i get invalid column name for ListU.SelectedValue , and the multi-part identifier "System.Data.DataRowView" could not be bound if i am using ListU.SelectedItem.
where did i go wrong? i am guessing it is either my code or it is my table.
private void User_Load(object sender, EventArgs e)
{
SqlDataAdapter daSearch = new SqlDataAdapter("SELECT cName FROM ComDet", conn);
DataTable dt1 = new DataTable();
ListU.DataSource = dt1;
daSearch.Fill(dt1);
ListU.ValueMember = "cName";
ListU.DisplayMember = "cName";
ListU.DropDownStyle = ComboBoxStyle.DropDownList;
ListU.Enabled = true;
}
and the button code -
private void searchBtn_Click(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection();
conn.ConnectionString = "Data Source=PEWPEWDIEPIE\\SQLEXPRESS;Initial Catalog=master;Integrated Security=True";
conn.Open();
SqlDataAdapter daS = new SqlDataAdapter("select cName, cDetails, cDetails2 from ComDet where cName =" + ListU.SelectedValue, conn);
DataTable dts3 = new DataTable();
daS.Fill(dts3);
dataGridView1.DataSource = dts3.DefaultView;
dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
conn.Close();
}

you should use SqlParameter ... helps against sql injection problems and also against missing quotes ... like this:
SqlDataAdapter daS = new SqlDataAdapter("select cName, cDetails, cDetails2 from ComDet where cName = #name", conn);
daS.SelectCommand.Parameters.Add("#name", SqlDbType.VarChar).Value = ListU.SelectedValue;
this assumes that cName is a string ... if not you'll have to change the SqlDbType ...

Related

c# display Access Database in DataGridView

First of all, here is my code:
private void Form5_Load(object sender, EventArgs e)
{
string strProvider = #"Provider = Microsoft.ACE.OLEDB.12.0; Data Source = c:\Users\name\Documents\myprogramms\example.accdb";
string strSql = "Select * from score";
OleDbConnection con = new OleDbConnection(strProvider);
OleDbCommand cmd = new OleDbCommand(strSql, con);
con.Open();
cmd.CommandType = CommandType.Text;
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataTable scores = new DataTable();
da.Fill(scores);
data_example.DataSource = scores;
}
My goal is to display the data out of a MS Access Database. My codes has no error messages, but everytime I try to open the Data Grid View its completely empty.
your code snippet looks good. I cannot see any obvious issue.
Try to put breakpoint at the end of your method and check if datatable contains rows and rows contains any values in ItemArray.
Make sure your data_example DataGridView control is set AutoGenerateColumns = true (default) and check you have no other data source defined for your data_example DataGridView control. This code works for me.
private void Form1_Load(object sender, EventArgs e)
{
data_example.AutoGenerateColumns = true;
string strProvider = #"Provider = Microsoft.ACE.OLEDB.12.0; Data Source = c:\aaa\CinemaBooking.accdb";
string strSql = "Select * from Booking";
using (OleDbConnection con = new OleDbConnection(strProvider))
{
using (OleDbCommand cmd = new OleDbCommand(strSql, con))
{
using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
{
con.Open();
var scores = new DataTable();
da.Fill(scores);
data_example.DataSource = scores.DefaultView;
con.Close();
}
}
}
}
Maybe you can try to fill dataset with adapter and then use named table as datasource:
var dtSet = new DataSet();
da.Fill(dtSet, "Booking");
data_example.DataSource = dtSet.Tables["Booking"].DefaultView;

Query single data from SQLite to C# textbox or label

I have a single SQlite query that returns "10" to me but I couldn't send it to c# textbox1.text area. I found datagrid examples which work just fine but single value for textbox I could not handle it.
I tried changing datagrid areas to textbox but really I have no idea how to get value with sqlite
private SQLiteConnection con = new SQLiteConnection();
private SQLiteCommand com = new SQLiteCommand();
private SQLiteDataAdapter adapt = new SQLiteDataAdapter();
private DataSet ds = new DataSet();
private DataTable dt = new DataTable();
//private SQLiteDataReader dr = new SQLiteDataReader();
public void set_connection()
{
con = new SQLiteConnection();
con.ConnectionString = ("Data Source=data/lastix_db.s3db");
}
public void execute_q(string txtQuery)
{
set_connection();
con.Open();
com = con.CreateCommand();
com.CommandText = txtQuery;
com.ExecuteNonQuery();
con.Close();
}
public void load_data()
{
set_connection();
con.Open();
com = con.CreateCommand();
string comtext = "SELECT * FROM stok";
adapt = new SQLiteDataAdapter(comtext, con);
ds.Reset();
adapt.Fill(ds);
dt = ds.Tables[0];
dataGridView1.DataSource = dt;
con.Close();
}
private void Button2_Click(object sender, EventArgs e)
{
set_connection();
string stokout = "SELECT SUM(giris_adet) - SUM(cikis_adet) as mevcutstok from stok where malzeme_kodu = 651";
execute_q(stokout);
label16.Text = Convert.ToString(stokout);
label16.Text = //must be read "10" from sqlite
Insert update delete and all other datagrid solutions are ok but I'm really stuck on read single data and type it to textbox.
SQLiteConnection connect = new SQLiteConnection();
connect.ConnectionString = ("Data Source=data/lastix_db.s3db");
connect.Open();
string sql = "SELECT SUM(giris_adet) - SUM(cikis_adet) as mevcutstok from stok where malzeme_kodu = 651";
SQLiteCommand cmd = new SQLiteCommand(sql, connect);
Int32 totalp = Convert.ToInt32(cmd.ExecuteScalar());
cmd.Dispose();
baglan.Close();
//MessageBox.Show("Your Balance is: " + totalp);
label16.Text = Convert.ToString(totalp);

Combobox SelectedValue Returning System.Data.DataRowView even Converted to String

I am trying to change value of a TextBox control after the value of ComboBox changes. My code returns System.Data.DataRowView on the first time ComboBox value changes.
That is why I am getting an Object instead of the actual value on first call to my combobox.
private void radioButton2_CheckedChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["myconnectionString"].ConnectionString);
con.Open();
SqlDataAdapter da = new SqlDataAdapter();
SqlCommand cmd= new SqlCommand("SELECT donor_name,ID FROM donor_detail",con);
cmd.CommandType = CommandType.Text;
da.SelectCommand = cmd;
DataTable dt = new DataTable();
da.Fill(dt);
DonorName.DataSource = dt;
DonorName.DisplayMember = "donor_name";
DonorName.ValueMember = "ID";
con.Close();
}
And this is Event of change Value of ComboBox which is supposed to change value of my TextBox also when value in ComboBox changes.
private void DonorName_SelectionChangeCommitted(object sender, EventArgs e)
{
var id = Convert.ToString(DonorName.SelectedValue);
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["myconnectionString"].ConnectionString);
con.Open();
String sql = "SELECT * from donor_detail WHERE ID=" + id + "";
SqlCommand cmd = new SqlCommand(sql,con);
SqlDataAdapter da = new SqlDataAdapter();
cmd.CommandType = CommandType.Text;
da.SelectCommand = cmd;
DataTable dt = new DataTable();
da.Fill(dt);
MessageBox.Show(sql);
mobile.Text = dt.Rows[0]["mobile"].ToString();
con.Close();
}
As mentioned here and several other places, this happens if you don't specify the datasource after the display and value members. This is the correct order:
DonorName.DisplayMember = "donor_name";
DonorName.ValueMember = "ID";
DonorName.DataSource = dt;

How to insert value from gridview into database

I have two tables in a SQL Server database. I select from table ADMS and I need to insert master table by gridview but I dont know how to insert with gridview. Please help. I've tried for many days and I did not pass yet
protected void Button3_Click1(object sender, EventArgs e)
{
if (RadioButton2.Checked)
{
SqlConnection con = new SqlConnection(MyConnectionString);
// con.Open(); // don't need the Open, the Fill will open and close the connection automatically
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM ADMS_Machining where datetime='" + TextBox1.Text + "'", con);
mytable = new DataTable();
da.Fill(mytable);
GridView2.DataSource = mytable;
GridView2.DataBind();
}
else
{
SqlConnection con = new SqlConnection(MyConnectionString);
// con.Open(); // don't need the Open, the Fill will open and close the connection automatically
SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM Machining_Master where datetime='" + TextBox1.Text + "'", con);
mytable = new DataTable();
da.Fill(mytable);
GridView2.DataSource = mytable;
GridView2.DataBind();
}
}
protected void Button4_Click(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection();
SqlCommand cmd = new SqlCommand();
String strConnString, strSQL;
strConnString = "Server=kane-pc;UID=sa;PASSWORD=1234;Database=Machining;Max Pool Size=400;Connect Timeout=600;";
//here
conn.ConnectionString = conn;
conn.Open();
cmd.Connection = conn;
cmd.CommandText = strSQL;
}
You can extract values from a grid view depending on what you have placed in the cells...
string value = this.GridView2.Rows[0].Cells[0].Text;
You can also track the selected row event, and get specific controls like the following...
protected void OnSelectedIndexChanged(object sender, EventArgs e)
{
string someValueTakenFromLabel = (GridView2.SelectedRow.FindControl("lblAnyLabelHere") as Label).Text;
// .... do something with value here
}
I suggest you go through some tutorials though to get the hang of how to use GridView.
http://www.asp.net/web-forms/videos/building-20-applications/lesson-8-working-with-the-gridview-and-formview
http://www.aspsnippets.com/Articles/How-to-get-Selected-Row-cell-value-from-GridView-in-ASPNet.aspx
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview%28v=vs.110%29.aspx
You have to first read data from cells and then insert them into database using SqlCommand.
Assuming that you have M_ID and M_NAME columns in your Machining_Master table you can insert values to database as below:
//Assuming that your id column is first column and name is second column
//get value of id and name
int mId = Convert.ToInt32(GridView2.SelectedRow.Cells[0].Text);
string mName = GridView2.SelectedRow.Cells[1].Text;
string connectionStrng = "your connection string";
string insertSql = "INSERT INTO Machining_Master (M_ID, M_NAME) VALUES (#mId, #mName)";
using (SqlConnection conn = new SqlConnection(connectionStrng))
{
using (SqlCommand cmd = new SqlCommand(insertSql, conn))
{
try
{
cmd.Parameters.Add(new SqlParameter("mId", mId));
cmd.Parameters.Add(new SqlParameter("mName", mName));
conn.Open();
cmd.ExecuteNonQuery();
}
finally
{
//Close connection
conn.Close();
}
}
}

sql search query in c#

I'm trying to make a database search in my app where the user would choose the column and enter the search word and the result would come up in a dataviewgrid.
This is the code i've been working on, the problem is that nothing comes up and i'm pretty sure there are entries in the database. EDIT : it's a windows form application
private void button1_Click(object sender, EventArgs e)
{
conn = new SqlConnection("Server = localhost; database = Clients; Integrated Security = SSPI");
conn.Open();
SqlCommand cmd = new SqlCommand("SELECT * From dbo.Tclients WHERE #choice = #input", conn);
cmd.Parameters.AddWithValue("#choice", comboBox1.Text);
cmd.Parameters.AddWithValue("#input", textBox1.Text);
ds = new DataSet();
da = new SqlDataAdapter(cmd);
da.Fill(ds);
dataGridView1.DataSource = ds.Tables[0];
conn.Close();
}
You cannot use a parameter to express the name of a column.
You should populate your combobox with the column names and set its DropDownStyle property to DropDownList (do not allow your user to type the name of the column) and then build your query
private void button1_Click(object sender, EventArgs e)
{
string cmdText = "SELECT * From dbo.Tclients WHERE " + comboBox1.Text + " = #input";
using(SqlConnection conn = new SqlConnection(....))
using(SqlCommand cmd = new SqlCommand(cmdText, conn))
{
conn.Open();
cmd.Parameters.AddWithValue("#input", textBox1.Text);
ds = new DataSet();
da = new SqlDataAdapter(cmd);
da.Fill(ds);
dataGridView1.DataSource = ds.Tables[0];
}
}
you forgot to bind the grid view with datasource
add this after data source
dataGridView1.DataSource = ds.Tables[0];
dataGridView1.DataBind();
private void bunifuThinButton21_Click(object sender, EventArgs e)
{
SqlConnection connection = new SqlConnection();
connection.ConnectionString = (#"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\albasheer\Desktop\games\my_school\my_school\school.mdf;Integrated Security=True;User Instance=True");
connection.Open();
string sql = "select name,id,stage,age,cost from STUDENT where stage like '%" + bunifuCustomLabel1.Text + "%' and name like '%" + bunifuMaterialTextbox1.Text + "%'";
SqlDataAdapter adapter = new SqlDataAdapter(sql, connection);
SqlCommand command = new SqlCommand(sql, connection);
DataTable table = new DataTable();
adapter.Fill(table);
var dt = from t in table.AsEnumerable()
select new
{
id = t.Field<int>("id"),
Name = t.Field<string>("name"),
};
bunifuCustomDataGrid1.DataSource = dt.ToList();
}

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