Searchable Dropdownlist - c#

I have dropdownlist filled by database. how can I make it searchable?
I can do it with some issues but when data bind with database in note working.
is my filling method wrong?
<asp:Label ID="lbProbType" runat="server" Text="Problem Type""
Font-Bold="True"></asp:Label>
if (!IsPostBack)
{
SqlConnection cn = new SqlConnection(#"");
string readnamesquery = "select cwFullTitle from tbCowWorkers order by cwLName";
cn.Open();
SqlCommand cmd = new SqlCommand(readnamesquery, cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
dpCaller.DataSource = dt;
dpCaller.DataTextField = "cwFullTitle";
dpCaller.DataBind();
cn.Close();
}

Related

Save edits from DataGridView to Datatable

Hi i want to save edits in DataGriView to datatable , i tried that code but an error shows 'System.ArgumentOutOfRangeException: 'The index was out of range. It must not be negative and must be smaller than the size of the collection.
Parameter name: index '' help
private void button11_Click(object sender, EventArgs e)
{
con.Open();
String query = "SELECT * FROM Taom";
SqlDataAdapter SDA = new SqlDataAdapter(query, con);
DataTable dt1 = new DataTable();
DataSet ds1 = new DataSet();
DataTable dt = new DataTable();
dataGridView1.DataSource = dt1;
SDA.Fill(dt);
dataGridView1.Rows[2].Cells[2].Value = Math.Atan((Convert.ToDouble(dataGridView1.Rows[5].Cells[2].Value)) / (Convert.ToDouble(dataGridView1.Rows[6].Cells[2].Value)));
dataGridView1.Rows[3].Cells[2].Value = Math.Atan((Convert.ToDouble(dataGridView1.Rows[7].Cells[2].Value)) / (Convert.ToDouble(dataGridView1.Rows[8].Cells[2].Value)));
ds1.Tables.Add(dt);
con.Close();}
I changed my code to that code no errors showed after i run values on datagridview change but no changes in datatable !!!
string query = "SELECT * FROM [dbo].[Taom]";
SqlConnection conn = new SqlConnection(#"Data Source=STE-P0024818PW;Initial Catalog=test;Integrated Security=True");
conn.Open();
SqlDataAdapter SDA = new SqlDataAdapter(query, conn);
DataSet ds1 = new DataSet();
DataTable dt = new DataTable();
SDA.Fill(dt);
dt.Rows[0]["Contents"] = "98"; //Before it was 10
dt.Rows[1]["Contents"] = "99"; //Before it was 11
ds1.Tables.Add(dt);
conn.Close();
Fill the right value inside your table and after pass the table rightly filled in your datasource, don't change this directly in the gridview like:
I try myself and it works:
private void Run()
{
string query = "SELECT * FROM dbo.[Anrufthema]";
SqlConnection conn = new SqlConnection("MyConnectionString");
conn.Open();
SqlDataAdapter SDA = new SqlDataAdapter(query, conn);
DataSet ds1 = new DataSet();
DataTable dt = new DataTable();
SDA.Fill(dt);
dt.Rows[0]["Anrufthema"] = "98"; //Before it was 10
dt.Rows[1]["Anrufthema"] = "99"; //Before it was 11
ds1.Tables.Add(dt);
conn.Close();
}
My Result, it works !

Updating Data GridView using the selected value inside the dropdown list

I have a dropdownlist and a gridview.. Dropdown list contains the list of the tables I have in my database. What I want is, when I select a particular table name from the dropdownlist, I want all the columns and data inside that particular table display inside the gridview.
This is my code...
Code for displaying the list of tables inside the dropdown is success.. But to bind the columns and data inside the gridview is not success..
Please Help me...
protected void Page_Load(object sender, EventArgs e)
{
using (SqlConnection con = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=Employee;Integrated Security=True"))
{
con.Open();
SqlCommand cmd = new SqlCommand("SELECT table_name FROM INFORMATION_SCHEMA.TABLES", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
DropDownList1.DataSource = ds;
DropDownList1.DataTextField = "table_name";
DropDownList1.DataValueField = "table_name";
DropDownList1.DataBind();
con.Close();
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
using (SqlConnection con = new SqlConnection("Data Source=.\\SQLEXPRESS;Initial Catalog=Employee;Integrated Security=True"))
{
con.Open();
SqlCommand cmd = new SqlCommand("SELECT * FROM INFORMATION_SCHEMA.columns where table_name='+ DropDownList1.selecteditem.text +'", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
GridView1.DataSource = ds;
//+DropDownList1.selecteditem.text +
GridView1.DataBind();
con.Close();
}
}
This is a bad idea on several levels. First you are wide open to SQL injection. Second, you are giving everyone full view access to every column and row of every table.
But the reason you are not getting data is because the select string does not make sense. It should look like this
"SELECT * FROM INFORMATION_SCHEMA.columns where table_name='" + DropDownList1.SelectedValue + "'"
But this is how a proper sql connection should look like.
//create a new datatable
DataTable dt = new DataTable();
//create the string that hold the query including token
string query = "SELECT * FROM INFORMATION_SCHEMA.columns where table_name = #TableName";
//create a new database connection
using (SqlConnection connection = new SqlConnection(ConnectionString))
using (SqlCommand command = new SqlCommand(query, connection))
{
command.CommandType = CommandType.Text;
//replace the token with the correct value
command.Parameters.Add("#TableName", SqlDbType.VarChar).Value = DropDownList1.SelectedValue;
//open the connection
connection.Open();
//load the data of the select into the datatable
dt.Load(command.ExecuteReader());
//bind the datatable to the gridview
GridView1.DataSource = dt;
GridView1.DataBind();
//but you can also skip the datatable and bind directly to the gridview
GridView1.DataSource = command.ExecuteReader();
GridView1.DataBind();
}

fill grid view in c#

I am new in using visual studio and ADO.NET. I want to display result from sqlserver database in data gridview.
This is my code but it does not fill data to gridview.
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection();
SqlCommand Cmd = new SqlCommand("sp_Expert_person", con);
con.Open();
Cmd.CommandType = CommandType.StoredProcedure;
Cmd.Parameters.Add("#takhasos", SqlDbType.VarChar).Value = comboBox1.SelectedText;
SqlDataAdapter da = new SqlDataAdapter(Cmd);
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(da);
DataTable dt = new DataTable();
da.Fill(dt);
SqlDataReader reader = Cmd.ExecuteReader();
dt.Load(reader);
dataGridView1.DataSource = dt;
this.dataGridView1.Visible = true;
dataGridView1.DataSource = dt;
}
Why are you binding to grid two times?
If your application is ASP.NET Webforms and you are trying to bind the GridView(ID for the GridView is "dataGridView1"), then make your binding to single time and to bind data for GridView you need to use dataGridView1.DataBind(); after dataGridView1.DataSource = dt;
If your application is WindowsForms application then modify your code like below
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
dataGridView1.DataSource = null;
string connectionString = "Define your connection string here";
using(SqlConnection con = new SqlConnection(connectionString ))
{
SqlCommand cmd = new SqlCommand("sp_Expert_person", con);
con.Open();
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("#takhasos", SqlDbType.VarChar).Value = comboBox1.SelectedText;
SqlDataAdapter da = new SqlDataAdapter(cmd);
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(da);
DataTable dt = new DataTable();
da.Fill(dt);
this.dataGridView1.Visible = true;
dataGridView1.DataSource = dt;
}
}

Databind to a Repeater

I am having a really hard time wrapping my head around the use of datatables. There for i been trying to use them more active, now this is where my issue surface.
This code returns no errors but no data is bound to the repeater:
Page:
<asp:Repeater ID="RepeaterBrand" runat="server">
<ItemTemplate>
<p><%# Eval("products_name")%></p>
</ItemTemplate>
</asp:Repeater>
Codebehind:
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["brand"] != null && !IsPostBack)
{
var Brand = (Request.QueryString["brand"]);
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
SqlCommand cmd = new SqlCommand("SELECT * FROM Table_Products WHERE products_brand = #Pr_brand", conn);
cmd.Connection = conn;
cmd.Parameters.Add("#Pr_brand", System.Data.SqlDbType.VarChar).Value = Brand;
DataTable dt = new DataTable();
conn.Open();
SqlDataReader reader = cmd.ExecuteReader();
if (reader.HasRows && reader.Read())
{
dt.Load(reader);
RepeaterBrand.DataSource = dt;
RepeaterBrand.DataBind();
}
conn.Close();
}
}
I'm quite new to C# so i might need some visual aid to get this.
Thank you in advance.
I hope this might help anyone this is what i ended up with after JaydipJ showed me the syntax.
if (Request.QueryString["brand"] != null && !IsPostBack)
{
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ToString());
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
var Brand = (Request.QueryString["brand"]);
cmd.CommandText = "SELECT * FROM Table_Products WHERE products_brand = #Pr_brand";
cmd.Parameters.Add("#Pr_brand", System.Data.SqlDbType.VarChar).Value = Brand;
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
adapter.Fill(dt);
RepeaterBrand.DataSource = dt;
RepeaterBrand.DataBind();
Don't read data from SQLDataReader. use it as it is to fill DataTable
if (reader.HasRows )
{
dt.Load(reader);
RepeaterBrand.DataSource = dt;
RepeaterBrand.DataBind();
}
Try This Code It's Working.
try
{
con.Open();
SqlCommand cmd = new SqlCommand("select Mst_Emp_Login.Emp_Uname from Mst_Emp_Login", con);
SqlDataAdapter adp = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
adp.Fill(ds);
Repeater1.DataSource = ds;
Repeater1.DataBind();
ds.Dispose();adp.Dispose();
cmd.Dispose();
con.Close();con.Dispose();
}
catch(Exception err)
{
throw err;
}

Display data in drop down based on another dropdown list

I have two drop down list in which i am getting data displayed from database.
When College Name in DropDownList2 is selected only related branches must be shown in of that college in DropDownList1 for this i had used a Stored Procedure and it was working fine when i run it in manually by passing Parameteres.
But while executing code i all branches are displayed.do i need have any Post Back ?
Please help me in this scenario.
Below is my code:
string queryString = "select College_Name from Colleges";
string constring = System.Configuration.ConfigurationManager.ConnectionStrings["ConnDBForum"].ConnectionString;
SqlConnection connection = new SqlConnection(constring);
SqlCommand command = new SqlCommand(queryString, connection);
connection.Open();
DataTable dt = new DataTable();
SqlDataAdapter ad = new SqlDataAdapter(command);
ad.Fill(dt);
if (dt.Rows.Count > 0)
{
DropDownList2.Items.Insert(0, new ListItem(String.Empty, String.Empty));
DropDownList2.DataSource = dt;
DropDownList2.DataTextField = "College_Name";
DropDownList2.DataValueField = "College_Name";
DropDownList2.DataBind();
DropDownList2.Items.Insert(0, new ListItem(String.Empty, String.Empty));
}
SqlCommand Cmd = new SqlCommand("Branch_display", connection);
Cmd.CommandType = CommandType.StoredProcedure;
Cmd.Parameters.Add(new SqlParameter("#College_Name", DropDownList2.SelectedValue));
DataTable dt1 = new DataTable();
SqlDataAdapter ad1 = new SqlDataAdapter(Cmd);
ad1.Fill(dt1);
if (dt1.Rows.Count > 0)
{
DropDownList1.DataSource = dt1;
DropDownList1.DataTextField = "Name";
DropDownList1.DataValueField = "Name";
DropDownList1.DataBind();
DropDownList1.Items.Insert(0, new ListItem(String.Empty, String.Empty));
}
connection.Close();
}
yes you need to have a post back somethink like this should help
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
string queryString = "select College_Name from Colleges";
string constring=System.Configuration.ConfigurationManager.ConnectionStrings["ConnDBForum"].ConnectionString;
SqlConnection connection = new SqlConnection(constring);
SqlCommand command = new SqlCommand(queryString, connection);
connection.Open();
DataTable dt = new DataTable();
SqlDataAdapter ad = new SqlDataAdapter(command);
ad.Fill(dt);
if (dt.Rows.Count > 0)
{
DropDownList2.Items.Insert(0, new ListItem(String.Empty, String.Empty));
DropDownList2.DataSource = dt;
DropDownList2.DataTextField = "College_Name";
DropDownList2.DataValueField = "College_Name";
DropDownList2.DataBind();
DropDownList2.Items.Insert(0, new ListItem(String.Empty, String.Empty));
}
connection.Close();
}
}
asp.net render
<asp:dropdownlist ID=" DropDownList2" runat="server" AutoPostBack="True" OnSelectedIndexChanged=" DropDownList2_SelectedIndexChanged">
and action
private void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
string constring=System.Configuration.ConfigurationManager.ConnectionStrings["ConnDBForum"].ConnectionString;
SqlCommand Cmd = new SqlCommand("Branch_display", connection);
Cmd.CommandType = CommandType.StoredProcedure;
Cmd.Parameters.Add(new SqlParameter("#College_Name", DropDownList2.SelectedValue));
DataTable dt1 = new DataTable();
SqlDataAdapter ad1 = new SqlDataAdapter(Cmd);
ad1.Fill(dt1);
if (dt1.Rows.Count > 0)
{
DropDownList1.DataSource = dt1;
DropDownList1.DataTextField = "Name";
DropDownList1.DataValueField = "Name";
DropDownList1.DataBind();
DropDownList1.Items.Insert(0, new ListItem(String.Empty, String.Empty));
}
connection.Close();
}

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