Must Declare the scalar variable "Post_ID" - asp.net

Question

I am getting this error "Must Declare the scalar variable "Post_ID" if i try to update 2 different ID's in my table. In other words, i can update as many times as i need to for example ID # 25 but if i try to update ID # 26 then i get the error above. My insert function works fine only my update function. Pls. help and i appreciate your time. Note, the DateKeyNames = ID. Here is my code for the update only:
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "UPDATE MyTable SET Post_ID=#Post_ID, Date=#Date, Description=#Description WHERE ID=#ID";
TextBox myTextBox11 = GV_InlineEditing.Rows[0].FindControl("GV_Post_ID") as TextBox;
TextBox myTextBox22 = GV_InlineEditing.Rows[0].FindControl("TextBox2") as TextBox;
TextBox myTextBox33 = GV_InlineEditing.Rows[0].FindControl("TextBox3") as TextBox;
if (myTextBox11 != null)
{
cmd.Parameters.Add("#Post_ID", SqlDbType.VarChar).Value = myTextBox11.Text;
}
else
{
TextBox GV_Post_ID = GV_InlineEditing.Rows[0].Cells[0].FindControl("GV_Post_ID") as TextBox;
}
if (myTextBox22 != null)
{
cmd.Parameters.Add("#Date", SqlDbType.VarChar).Value = myTextBox22.Text;
}
else
{
TextBox GV_Post_ID = GV_InlineEditing.Rows[0].Cells[0].FindControl("Date") as TextBox;
}
if (myTextBox33 != null)
{
cmd.Parameters.Add("#Description", SqlDbType.VarChar).Value = myTextBox33.Text;
}
else
{
TextBox GV_Post_ID = GV_InlineEditing.Rows[0].Cells[0].FindControl("Description") as TextBox;
}
cmd.Parameters.Add("#ID", SqlDbType.Int).Value = Convert.ToInt32(GV_InlineEditing.Rows[e.RowIndex].Cells[1].Text);
cmd.Connection = con;
con.Open();
cmd.ExecuteNonQuery();
con.Close();
}
GV_InlineEditing.EditIndex = -1;
BindData();

Answer 1

Your logic is somewhat faulty:
if (myTextBox11 != null)
{
//add paramter
cmd.Parameters.Add("#Post_ID", SqlDbType.VarChar).Value = myTextBox11.Text;
}
else
{
//declare a different textbox and do not add the SQL parameter
TextBox GV_Post_ID = GV_InlineEditing.Rows[0].Cells[0].FindControl("GV_Post_ID") as TextBox;
}
This pattern is repeated for myTextBox22 and myTextBox33.
I would suggest this logic instead:
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString);
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "UPDATE MyTable SET Post_ID=#Post_ID, Date=#Date, Description=#Description WHERE ID=#ID";
TextBox myTextBox11 = GV_InlineEditing.Rows(0).FindControl("GV_Post_ID") as TextBox;
TextBox myTextBox22 = GV_InlineEditing.Rows(0).FindControl("Date") as TextBox;
TextBox myTextBox33 = GV_InlineEditing.Rows(0).FindControl("Description") as TextBox;
if (myTextBox11 == null) {
//try an alternate control for myTextBox11
myTextBox11 = GV_InlineEditing.Rows(0).Cells(0).FindControl("GV_Post_ID") as TextBox;
}
if (myTextBox22 == null) {
//try an alternate control for myTextBox22
myTextBox22 = GV_InlineEditing.Rows(0).Cells(0).FindControl("Date") as TextBox;
}
if (myTextBox33 == null) {
//try an alternate control for myTextBox33
myTextBox33 = GV_InlineEditing.Rows(0).Cells(0).FindControl("Description") as TextBox;
}
if (myTextBox11 != null & myTextBox22 != null & myTextBox33 != null) {
//all three textbox controls found
cmd.Parameters.Add("#Post_ID", SqlDbType.VarChar).Value = myTextBox11.Text;
cmd.Parameters.Add("#Date", SqlDbType.VarChar).Value = myTextBox22.Text;
cmd.Parameters.Add("#Description", SqlDbType.VarChar).Value = myTextBox33.Text;
cmd.Parameters.Add("#ID", SqlDbType.Int).Value = Convert.ToInt32(GV_InlineEditing.Rows(e.RowIndex).Cells(1).Text);
cmd.Connection = con;
con.Open();
cmd.ExecuteNonQuery();
con.Close();
}
UPDATE
Add else conditions to Throw New Exception("myTextBox11 is null"); for myTextBox11, myTextBox22, and myTextBox33.
That will allow you to see if both:
GV_InlineEditing.Rows(0).FindControl("Date") as TextBox;
and:
GV_InlineEditing.Rows(0).Cells(0).FindControl("GV_Post_ID");
are failing.

Answer 2

I always do something like this like this:
protected void Gridview1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
int id = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
TextBox date = (TextBox)row.FindControl("date");
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "update t_your_table " +
"set " +
"date = #date, " +
" time = #time where id = #ID "
cmd.Parameters.Add("#id", SqlDbType.VarChar).Value = id;
cmd.Parameters.Add("#date", SqlDbType.VarChar).Value = date.Text;
You have to get your datakeyname into the variables. That way it will use that field no matter what row is clicked.