此代碼產生錯誤..「System.InvalidCastException：指定的轉換無效。」

-1

cmd1.CommandText = "SELECT distinct MbrBtch from Member where MbrStrm='"+DrpDwnStrm .SelectedItem .Text +"'"; 
      cmd1.Connection = con; 
      DataTable Table1; 
      Table1 = new DataTable("mbr"); 
      DataRow Row1; 
      DataColumn MbrBatch = new DataColumn("MbrBatch"); 
      MbrBatch.DataType = System.Type.GetType("System.Int32"); 
      Table1.Columns.Add(MbrBatch); 
      try 
      { 
       con.Open(); 
       SqlDataReader RdrMbr = cmd1.ExecuteReader(); 
       while (RdrMbr.Read()) 
       { 

        Row1 = Table1.NewRow(); 
        Row1["MbrBatch"] = Convert.ToInt32(RdrMbr.GetInt32(0)); 
        Table1.Rows.Add(Row1); 
       } 
       RdrMbr.Close(); 
      } 

      finally 
      { 
       con.Close(); 
      } 
      DrpDwnBtch.DataSource = Table1; 
      this.DrpDwnBtch.DataTextField = "MbrBatch"; 
      DrpDwnBtch.DataBind(); 

//here MbrBtch is numeric type attribute of sql server.

來源

2012-04-27 user1283405

哪裏？你有什麼嘗試？等 – Keith 2012-04-27 17:06:45

哪一行錯誤？ – 2012-04-27 17:06:57

您的查詢很容易受到SQL注入的影響。使用參數化查詢。 – 2012-04-27 17:07:50

我的猜測是下面的一行會給你一個錯誤。

更改線路

Row1["MbrBatch"] = Convert.ToInt32(RdrMbr.GetInt32(0));

與

int mbr = 0; 
if (Int32.TryParse(RdrMbr[0], out mbr)) 
    Row1["MbrBatch"] = mbr;

來源

2012-04-27 17:15:54 RajN

是否有可能有在MbrBtch列空值？如果是這樣，你需要像這樣檢查空值：

if (!RdrMbr.IsDBNull(0)) 
    Row1["MbrBatch"] = Convert.ToInt32(RdrMbr.GetInt32(0)); 
else 
    // Set value to what it should be if null, perhaps a -1 or 0

來源

2012-04-27 17:44:07 JoshL

此代碼產生錯誤..「System.InvalidCastException：指定的轉換無效。」

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