Question

I am using a asp.net grid view to load data from my sql data table.I am able to successfully load the data.

Sql Table Desgin:
3 cloumns:Location,Firstname,LastName

Location is the primary key.

Design :

Aspxpage has a gridview which has two buttons in the bottom:

1. Edit
2. Save

When user hits Edit button all the cells in the gridview are made editable so that user can edit and save the values.

My problem arises with the save button where i am unable to save the edited data back to the SQL.

Here is the code for the save button click:

protected void btnSave_Click(object sender, EventArgs e)
{
    int RowIndex=0;

    GridViewRow row = (GridViewRow)gvres.Rows[RowIndex];

    TextBox txtLanguage1 = row.FindControl("txtFName") as TextBox;
    TextBox txtLanguage2 = row.FindControl("txtLName") as TextBox;

    SqlConnection myConnection = new SqlConnection(connectionString);
    SqlCommand cmd = new SqlCommand("UPDATE UsersTable SET FirstName = @FirstName, LastName = @LastName WHERE Location = @Location", myConnection);


    cmd.Parameters.AddWithValue("@FirstName", txtFirstName.Text.Trim());
    cmd.Parameters.AddWithValue("@LastName", txtLastName.Text.Trim());

    myConnection.Open();
    cmd.ExecuteNonQuery();
    gvusers.EditIndex = -1;
    DataBind();
}

Exception:“Must declare the scalar variable “@Location”.”

Answer 1

You need to add a parameter to the SqlCommand object named “@Location”. You mention that Location is one of the columns in your grid—you can either read the value from the column (similar to how you are getting the first and last name values), or you can specify “Location” as the data key, and get it from the DataKeys property of the grid.

I’d look at the ASP.NET Real World Controls project on Codeplex. It allows for bulk editing and it smart enough to only update the rows that have changed.