dynamically bind item template , edit template to gridview codebehind

I have multiple tables which need to be bind to the asp.net grdiview at run time during code behind: one such table example is the employee mapping table which will be bind to grid view.

At the time of editing the grid view, we need to bind the dropdown to some of the columns and these columns display dropdown at the time of editing the data rows. and each dropdown will be sourced for different tables and different select and display fields.

for the city, it has been multi-select dropdown values when the grid is in edit mode. can this be done?

employee_mapping
id	employee id	qualificationid	cityid
100	232	161	86,87
101	233	162	85,84

qualification
qualificationid	qualificationname
161	BE (IT)
162	Btech (CSE)
163	MSCIT
164	MBBS

city table
city id	city name
86	Rajkoat
87	ahmedabad
88	pune

Employee table
employeeid	emplyeename
232	Nilesh
233	purnima

once the gridview is loaded, it should display the employee_mapping table by joining city and qualification tables to show cityname and qualificationname instead of their ids in gridview.

once grdiview is in edit mode , dropdown should be visible: in dropdown, data display field should be "qualification Name" and data selected value field must be "qualification id" from qualification table.

can we do this at run time using code behind .?

for simple bound fields, we can do simply as :

BoundField nameColumn = new BoundField();
nameColumn.DataField = "mappingID";
nameColumn.HeaderText = "Employee ID"; 
GridView1.Columns.Add(nameColumn);

but how to bind the template fields and item template and edit item templates along with multi select dropdowns and saving the values to database?

there are just 3 steps.

1. Design a grid with an item template and an Edit Item template. In the Item template, all columns will be simple bound fields but in the Edit item template, there will be a dropdown for qualification and cities.

"g" DataKeyNames="EmployeeId" runat="server" AutoGenerateColumns="false"
OnRowEditing="Edit" OnRowDataBound="RowDataBound" OnRowUpdating="Update"
OnRowCancelingEdit="CancelEdit">
"EmployeeId" HeaderText="EmployeeId" />
"EmployeeName" HeaderText="EmployeeName" />
"Qualification">
"lblQualification" runat="server" Text='<%# Eval("Qualification")%>'>
"ddlQualification" runat="server">
"City">
"lblCity" runat="server" Text='<%# Eval("City")%>'>
"ddlCity" runat="server">
"True" />

populating the gridview

protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
this.BindGrid();
}
}
private void BindGrid()
{
string sql = "Join all tables here";
string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection con = new SqlConnection(conString))
{
using (SqlDataAdapter sda = new SqlDataAdapter(sql, con))
{
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
gv.DataSource = dt;
gv.DataBind();
}
}
}
}

3. On row bound

protected void RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow && gvCustomers.EditIndex == e.Row.RowIndex)
{
DropDownList ddlCities = (DropDownList)e.Row.FindControl("ddlCities");
string sql = "SELECT DISTINCT City FROM City";
string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection con = new SqlConnection(conString))
{
using (SqlDataAdapter sda = new SqlDataAdapter(sql, con))
{
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
ddlCities.DataSource = dt;
ddlCities.DataTextField = "CityName";
ddlCities.DataValueField = "CityId";
ddlCities.DataBind();
string selectedCity = DataBinder.Eval(e.Row.DataItem, "City").ToString();
ddlCities.Items.FindByValue(selectedCity).Selected = true;
}
}
}
}
}

protected void Update(object sender, GridViewUpdateEventArgs e)
{
string city = (gv.Rows[e.RowIndex].FindControl("ddlCities") as DropDownList).SelectedItem.Value;
string EmployeeId = gv.DataKeys[e.RowIndex].Value.ToString();
string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
using (SqlConnection con = new SqlConnection(conString))
{
string query = "UPDATE query";
using (SqlCommand cmd = new SqlCommand(query, con))
{
cmd.Parameters.AddWithValue("@CustomerId", customerId);
cmd.Parameters.AddWithValue("@City", city);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
Response.Redirect(Request.Url.AbsoluteUri);
}
}
}

This was just a template, you need to understand and resolve it by yourself.

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
Accepted answer
there are just 3 steps.
1. Design a grid with an item template and an Edit Item template. In the Item template, all columns will be simple bound fields but in the Edit item template, there will be a dropdown for qualification and cities.
"g" DataKeyNames="EmployeeId" runat="server" AutoGenerateColumns="false"
    OnRowEditing="Edit" OnRowDataBound="RowDataBound" OnRowUpdating="Update"
    OnRowCancelingEdit="CancelEdit">

        "EmployeeId" HeaderText="EmployeeId" />
   "EmployeeName" HeaderText="EmployeeName" />
        "Qualification">

                "lblQualification" runat="server" Text='<%# Eval("Qualification")%>'>


                "ddlQualification" runat="server">



"City">

                "lblCity" runat="server" Text='<%# Eval("City")%>'>


                "ddlCity" runat="server">



        "True" />


populating the gridview
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindGrid();
    }
}

private void BindGrid()
{
    string sql = "Join all tables here";
    string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlDataAdapter sda = new SqlDataAdapter(sql, con))
        {
            using (DataTable dt = new DataTable())
            {
                sda.Fill(dt);
                gv.DataSource = dt;
                gv.DataBind();
            }
        }
    }
}
3. On row bound
protected void RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow && gvCustomers.EditIndex == e.Row.RowIndex)
    {
        DropDownList ddlCities = (DropDownList)e.Row.FindControl("ddlCities");
        string sql = "SELECT DISTINCT City FROM City";
        string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(conString))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter(sql, con))
            {
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    ddlCities.DataSource = dt;
                    ddlCities.DataTextField = "CityName";
                    ddlCities.DataValueField = "CityId";
                    ddlCities.DataBind();
                    string selectedCity = DataBinder.Eval(e.Row.DataItem, "City").ToString();
                    ddlCities.Items.FindByValue(selectedCity).Selected = true;
                }
            }
        }
    }
}
protected void Update(object sender, GridViewUpdateEventArgs e)
{
    string city = (gv.Rows[e.RowIndex].FindControl("ddlCities") as DropDownList).SelectedItem.Value;
    string EmployeeId = gv.DataKeys[e.RowIndex].Value.ToString();
    string conString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(conString))
    {
        string query = "UPDATE query";
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            cmd.Parameters.AddWithValue("@CustomerId", customerId);
            cmd.Parameters.AddWithValue("@City", city);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
            Response.Redirect(Request.Url.AbsoluteUri);
        }
    }
}
This was just a template, you need to understand and resolve it by yourself.