CODEWITHSUNDEEP
c#asp.netmergedatatable
thevan
thevan

Reputation: 10354

DataTable.Merge throws Error: Object reference not set to an instance

I want to merge datatables in the DropDownList selectedindex changed event. So I have written the below code in the DropDownList_SelectedIndexChanged Event. 

    DataTable dt = (DataTable)POBLL.GetPOAdhocDetail();
    DataView dv = new DataView(dt);
    dv.RowFilter = "IndentTypeID = " + ddlIndentType.SelectedValue + "AND IndentID = " + ddlIndentNumber.SelectedValue;
    DataTable dtView = dv.ToTable();        
    gvPODetails.DataSource = dtView;
    gvPODetails.DataBind();
    DTMerge.Merge(dtView);

where DTMerge is the DataTable and I declared it like below:

   public DataTable DTMerge
   {
      get
      {
        if (ViewState["Merge"] != null)
        {
            return (DataTable)ViewState["Merge"];
        }
        else
            return null;
      }
      set
      {
         ViewState["Merge"] = value;
      }
  }

But it throws the Error "Object reference not set to an instance". How to solve this?

Upvotes: 1

Views: 2942

Answers (1)

Tigran
Tigran

Reputation: 62266

You requested DTMerge property, which for being valid need of presence of corresponding ViewState. You don't have a ViewState yet, at the moment you access DTMerge property.

This is most likely the problem.

Upvotes: 2

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