Question

I am trying to do the text box autocomplete by using the code below, but it gives the error

ERROR :"Object reference not set to an instance of an object"

on this line:

for (int count = 0; count < dt.Rows.Count; count++)

Can anyone please help me?

private void tbMemberName_TextChanged_1(object sender, EventArgs e)
{
    tbMemberName.AutoCompleteMode = AutoCompleteMode.Suggest;
    tbMemberName.AutoCompleteSource = AutoCompleteSource.CustomSource;
    AutoCompleteStringCollection namec = new AutoCompleteStringCollection();

    //string search ="%"+ tbMemberName.Text +"%";
    //string @Name = tbMemberName.Text; 
    String sql =
        @"SELECT DISTINCT(member_Firstname +''+ member_Lastname) AS Name FROM members WHERE Name  Like '%'+tbMemberName.Text+'%'";
    DataTable dt = MemberFormHelper.GetData(sql, mf);
    if (dt.Rows.Count >= 0)
    {
        for (int count = 0; count < dt.Rows.Count; count++)
        {
            namec.Add(dt.Rows[count][Name].ToString());
        }
    }
    tbMemberName.AutoCompleteCustomSource = namec;
}

Answer 1

dt is null, prolly (unless u have a record in ur table with the following name ‘tbMemberName.Text’)… I guess so – tbMemberName is a TextBox, so if you are trying to pass its value to the sql string instead of

@"SELECT DISTINCT(member_Firstname +''+ member_Lastname) AS Name FROM members WHERE Name Like '%'+tbMemberName.Text+'%'";

u have to write

@"SELECT DISTINCT(member_Firstname +''+ member_Lastname) AS Name FROM members WHERE Name Like '%"+tbMemberName.Text+"%'";

u have just misused quotation marks.