Gridview fields values does not change on update - asp.net

Question

I have a gridview and i want to modify some fields on gridview.This fields value not change when i click on Update button.I tried use Postback control but this problem keep going.How can i solve this problem?
ASPX code
<asp:GridView ID="gview" runat="server" AutoGenerateColumns="False" EnableModelValidation="True" GridLines="Horizontal" OnRowDataBound="gview_RowDataBound" OnRowEditing="gview_RowEditing" OnRowUpdating="gview_RowUpdating" OnRowCancelingEdit="gview_RowCancelingEdit">
<Columns>
<asp:BoundField DataField="SubCategoryId" HeaderText="ID" InsertVisible="False" ReadOnly="True"
SortExpression="SubCategoryId" />
<asp:TemplateField HeaderText="Category">
<ItemTemplate>
<asp:Label ID="lblCategory" runat="server"></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:DropDownList ID="ddlCategory" DataValueField="CategoryId" DataTextField="CategoryName" runat="server" />
</EditItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="CategoryName" HeaderText="Category Name" SortExpression="CategoryName" />
<asp:CommandField ButtonType="Link" EditText="Edit" HeaderText="Edit"
ShowEditButton="True" ShowHeader="False" CancelText="Cancel" UpdateText="Update" />
</Columns>
</asp:GridView>
C# code
protected void gview_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Label lbl = e.Row.FindControl("lblCategory") as Label;
DropDownList ddl = e.Row.FindControl("ddlCategory") as DropDownList;
if ((e.Row.RowState & DataControlRowState.Edit) > 0)
{
ddl.DataSource = LoadCategories();
ddl.DataBind();
}
if (lbl != null)
{
lbl.Text = GetCategoryName(Convert.ToInt32(gview.DataKeys[e.Row.RowIndex][0]));
}
}
}
protected void gview_RowEditing(object sender, GridViewEditEventArgs e)
{
gview.EditIndex = e.NewEditIndex;
SubCategoryLoad();
}
protected void gview_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
int categoryId, subCategoryId;
string categoryName;
DropDownList ddl = (DropDownList)gview.Rows[e.RowIndex].FindControl("ddlCategory");
subCategoryId = int.Parse(gview.Rows[e.RowIndex].Cells[0].Text);
categoryId = int.Parse(ddl.SelectedValue);
categoryName = gview.Rows[e.RowIndex].Cells[2].Text;
gview.EditIndex = -1;
UpdateSubCategory(subCategoryId,categoryName,categoryId);
SubCategoryLoad();
}
public void SubCategoryLoad()
{
using (SqlConnection conn = new SqlConnection(DataBase.Conn))
{
conn.Open();
string query = "SELECT * FROM dbo.SubCategories";
using (SqlDataAdapter da = new SqlDataAdapter(query, conn))
{
DataTable dt = new DataTable();
da.Fill(dt);
gview.DataSource = dt;
gview.DataBind();
}
}
}
public int UpdateSubCategory(int subCategoryId, string categoryName, int categoryId)
{
using (SqlConnection conn = new SqlConnection(DataBase.Conn))
{
conn.Open();
string query = "UPDATE dbo.SubCategories SET CategoryId = #categoryId, CategoryName = #categoryName WHERE SubCategoryId = #id";
using (SqlCommand cmd = new SqlCommand(query, conn))
{
cmd.Parameters.AddWithValue("#id", subCategoryId);
cmd.Parameters.AddWithValue("#categoryName", categoryName);
cmd.Parameters.AddWithValue("#categoryId", categoryId);
return (int)cmd.ExecuteNonQuery();
}
}
}

Answer 1

Please check have you bind gridview inside
if(!page.ispostback)
{
}

Answer 2

You must update the data to the actual datasource and rebind it.
If you have updated the values then you shall rebind the GridView again with updated values
mGridView.DataSource = {YOUR DATA SOURCE};
mGridView.DataBind();
EDIT 1:
Does this method being called break there check that
have you set update as
commandText ="Update"